1. Field of the Invention
The present invention relates to a filling method and device.
The invention more particularly relates to a method for filling a tank with pressurized gas, comprising transfer of a predefined amount of a gas into the tank from at least one pressurized gas source via a filling duct, the gas being selectively cooled by a cooling component before it enters into the tank in order to prevent a defined temperature limit from being reached in the tank.
2. Related Art
Rapidly filling a tank with pressurized hydrogen gas produces an accumulation of heat in the tank (mainly due to compression of the gas during filling). This accumulation of heat leads to heating of the tank, which may cause the tank to reach or exceed its temperature limit (Tc), above which limit (85° C., for example, for a composite tank) the tank loses its ability to withstand pressure. In order to prevent this, it is known to pre-cool the gas before it enters into the tank. The higher the initial temperature of the gas added, the greater this pre-cooling must be.
One problem with this solution is that it is relatively difficult:                to evaluate with precision the cooling required;        to apply the required cooling continuously; and        to check whether the required cooling has been correctly carried out.        
One known solution consists in defining a temperature at which the gas must be cooled before it enters the tank throughout the filling process.
For example the standard SAE TIR J2601 specifies that, for rapid filling operations (no more than five minutes in length) and for final pressures of 35 MPa to 70 MPa, the hydrogen gas must be pre-cooled to a temperature between −40° C. and −33° C., throughout the filling operation.
These pre-cooling temperatures were selected using temperature prediction models, in order to stop the temperature of the gas in the tank exceeding 85° C. at the end of the filling operation.
However, this solution has the following drawbacks:                the amount of cooling required is generally overestimated in order to accommodate every type of tank liable to need filling, this overestimation is further increased when the temperature limit is applied to the gas in the tank and not to the walls of the tank itself;        the refrigeration that must be applied to the gas in order to achieve a constant pre-cooling temperature throughout the filling process varies significantly, hence the required refrigerating power is inefficiently used;        reliably maintaining the hydrogen temperature between −40° C. and −33° C. throughout the filling operation is relatively complex and costly because these temperatures are near the lowest that can be produced industrially on a large scale;        there is a risk that elastomer seals in the filling installation will deteriorate at these low temperature levels, moreover other components must not be exposed to temperatures below −40° C.; and        such low temperatures cause frost to form on the equipment, which may impair proper operation of the installation.        